The objective of this Core Unit is to provide a central mechanism to assist investigators with the design and execution of hematopoietic stem cell transduction studies in dogs and non-human primates. The Core Unit will provide three main functions. The first function, the design and the planning of the large animal experiments will involve the provision of dogs and monkeys for the individual studies. The Core Unit director will ensure that animals will be available and adequately prepared for the individual studies. The second function involves the actual stem cell harvest and the reinfusion of transduced cells. Marrow stem cells will be given to the individual investigators for further processing and transduction. Before reinfusion of transduced cells the animals will receive a myeloablative dose of total body irradiation. Monkeys will receive an intravenous catheter that is connected via a tether system to the outside of the cage. This facilitates the daily administration of fluids and broad-spectrum antibiotics and will also be used for reinfusion of transduced cells. The third function involves the post-transplant monitoring and care of the animals. All animals will be examined daily by the Core Unit director and health status and treatment plan will be discussed with specially trained personnel at the Primate Center and the Canine Facility. The Primate Center at the University of Washington has set aside a special room for our nonhuman primate studies to accommodate the intensive care required for these studies. The staff at the Primate Center and the Canine Faculty is specially trained to work with animals involved in stem cell transplantation studies. In many ways, the operations of this large animal stem cell unit is modeled after a human stem cell transplantation unit to assure the high quality care required for these studies.